To increase the driving capability of a liquid crystal display device, single-crystal silicon tends to be used as a semiconductor for a display region and peripheral region. This is an attempt to form a driving element, switching element, and the like on a single-crystal silicon substrate surface. FIG. 4 shows an example.
Referring to FIG. 4, reference numeral 1 denotes a single-crystal silicon substrate; 6, a LOCOS insulating layer; 7, a light-shielding layer; 8, an insulating layer; 12, a reflecting electrode; 13, a pixel electrode; 14, a liquid crystal layer; 15, a common transparent electrode; 20, a switching element and the like; 21, a peripheral circuit; 111, a display region; 112, a peripheral region; and 51, a sealing material. Details of the switching element and the like are not illustrated. The switching element and the like and the peripheral circuit are formed using the single-crystal silicon substrate as a base to increase the driving capability.
When a single-crystal silicon substrate is used as the active layer of a driving element and the like, the driving capability may degrade due to heat generated from the driving element and the like. In addition, when micropatterning/integrating techniques for semiconductor devices are frequently used to form peripheral circuits, the chip heat density from these circuits may greatly increase.
To solve these problems, a technique is used to grind a semiconductor region 55 from a lower surface 52 side of the substrate using a back grinder to make the semiconductor device thin.
However, since the most part of the substrate is ground, the technique using a back grinder is not preferable for effective use of limited resources. Furthermore, even with this grinding technique, the device can be made as thin as only several hundred μm. Hence, no sufficient measure against heat generation can be obtained.